Mechanics of filled rubbers from a molecular point of view

Since almost a century, the addition of nanofillers, which are mainly carbon black or silica particles, to rubbery polymers (elastomers) has been used primarily for improving the mechanics of commercial elastomers in the market and for research. These formulations normally introduce many other ingredients such as cross-linkers, catalyzers and so on, for improving filler dispersion and altering certain characteristics of the final materials, particularly their mechanical characteristics. Such complex chemical formulations and lack of knowledge about spectroscopic and microscopic properties of nanocomposites are two fundamental challenges for explaining the effect of nanofiller chemistry and morphology on the nanocomposite macroscale viscoelasticity. The central idea of this thesis can be expressed as ‘molecular scale explanation of the linear and non-linear elastic properties of industrial nanocomposites by inclusion of nano-size silica fillers’. In the content of this thesis, I tried to answer some sub-questions stemming from this main idea. In order to address the sub-questions, I always tried to find the answer in a ‘triangle of data’ consisting of molecular spectroscopy (physical chemistry), electron microscopy (structure) and mechanical characterization (mechanics) of silica filled rubber systems.